Channel Flow Transition Induced by a Pair of Oblique Waves

Abstract

A pair of small but finite amplitude oblique waves were used as initial condition in numerical simulations of transition to turbulent flow. A number of cases were run with different combinations of Reynolds numbers and initial wave characteristics. In all cases a rapid energy growth to a transition peak occurred, followed by a redistribution of the energy to smaller spatial scales. The flow fields after the peak resembled that of a turbulent state although no attempts were made to determine whether these states were sustained. The reported transition process represents a bypass of the secondary instability scenario involving finite amplitude 2D waves.